In principle you are correct. But in practice, renicing a process to the highest priority is the most efficient tactic for keeping it running on a single CPU as continuously as possible while not disrupting the rest of the system (see man sched_setscheduler on why). There's also taskset, which actually influences processor affinity (which is what you are talking about), but that doesn't have much practical use for this particular case. In fact, if you want your process to run on a CPU core as continuously as possible (and you're not fussy about which exact core it is, which I don't see why the OP would be), then you want the OS scheduler to switch the process to a different core for the very rare case when this is more efficient. Thus, setting processor affinity would do more harm than good.